An appellate panel should limit the scope of California's Proposition 69, which authorized DNA collection of anyone arrested on suspicion of a felony.

In 2004 California voters approved Proposition 69, which authorized the collection of DNA evidence not just from convicted offenders and people arrested for homicide or sex crimes, but from anyone arrested on suspicion of a felony. The profiles generated from samples obtained under the law are shared with police in other states.

This page opposed the measure as overly broad. It's one thing to build a database of samples from convicted criminals, but it's quite another to keep genetic profiles of people who are arrested but ultimately determined to be innocent of any crime. So we're heartened that the U.S. 9th Circuit Court of Appeals has agreed to revisit its constitutionality. A three-judge panel of the 9th Circuit upheld Proposition 69 by a 2-1 vote, but now the law will be reviewed by 11 judges. (On Monday, in connection with a similar Maryland law, Chief JusticeJohn G. Roberts Jr. suggested that the Supreme Court will eventually rule on laws like the one at issue in California.)

The law is not as outrageous or Orwellian as some of its critics maintain. For example, the DNA is acquired by the relatively noninvasive method of a cheek swab, which is often performed by the suspect himself. And the resulting profiles involve so-called junk DNA, which does not include information about the arrestee's propensity to disease. Still, the law blurs the distinction between suspicion and guilt, and if a person is ultimately not charged or not convicted, he must take affirmative steps to have his profile removed from the system.

In his majority opinion for the panel, Judge Milan D. Smith Jr. asserted that DNA profiles, like fingerprints, are taken in order to ascertain the arrestee's identity. But they are also intended to aid in the investigation of other crimes, past and future.

As soon as the profile enters the system, authorities can check it against profiles already in the database, including those from samples gathered at the scenes of unsolved crimes. If charges are dropped, an arrestee can petition the court for expungement of his DNA information, but expungement can't be ordered until 180 days after the arrestee's request. If charges aren't officially dismissed, the arrestee must wait to request an expungement until expiration of the statute of limitations for the crime for which he was arrested.

The appeals court panel found that this system did not unduly infringe on the 4th Amendment privacy rights of the plaintiffs, who included protesters arrested during political demonstrations. The majority made much of the fact that the plaintiffs had been arrested on probable cause that they had committed a crime. But, as dissenting Judge William A. Fletcher pointed out, the relevant transaction occurs when the suspect's profile is matched against others on the database to determine if he is implicated in other crimes. For those crimes, Fletcher said, "there is no probable cause."

This might seem like legal hair-splitting, but it highlights Proposition 69's troubling purpose: to expand the DNA database to include the names of people who under the law are as innocent as those who have never been arrested. That goes a step too far.